Smile (Lip) Line

How many teeth you show when you smile or speak and how much of each tooth (length) is displayed when you smile broadly or (at the opposite end of the spectrum) when your lips are at rest functions of where your upper lip attaches to your face and how old you are.

There are three classifications of “lip line” that dentist use—low, medium, and high. A low lip line is one in which very little of your teeth are visible when you talk or smile. Someone with a low lip line will show, at most, a millimeter or two of the edge of the biting edge of the tooth. A medium lip line will allow most of the tooth, up to and including a millimeter or two of the gum tissue, to be visible. A person with a high lip line will show all the top front teeth and significant amount of gum tissue when speaking or smiling.

Dentists (and plastic surgeons) have not been very successful in surgically changing the low, medium, or high lip line. There are some dental “tricks” that can be used in limited situations to reduce the amount of gum display evident with a high smile line. Most of the corrective procedures to improve the esthetics of the situation require significant investments of both time and money. Periodontal (gum) surgery, alone or in conjunction with porcelain veneers or ceramic crowns, is more likely. In extreme cases the only option may be to surgically reposition the entire maxilla (with or without orthodontics). Conversely, the appearance of showing no teeth when talking or smiling is regarded as one associated with advanced aging.  

There is another component to how much of your teeth show when your lips are at rest, and it has to do with gravity and time. Your face and lips are composed of soft tissue that is under a constant gravity challenge. Gravity always wins, given enough time. The skin and subskin tissues drop over the years. If, with your lips at rest, you showed about 3 mm of the biting edges of the top two front teeth when you were 20 years old, by the time you are 40, you may show only 2 mm of edge. Someone 50 years of age would show 1 mm, and at 60 years, maybe not tooth is seen when the lips are at rest. The tissues of the human face will drop about 1 mm every 10 years, beginning around age 40. As the facial tissues lose elasticity, they slowly drop. Obviously, some lucky people have better genetics and their faces will stay tighter and the tissue drop will be slower. Correcting the age-related facial tissue drop can be done with plastic surgery—the common face lift.

Genetics or Gravity? If you are reading this, then you have either asked questions about your smile and lip line or this issue has been addressed in the broader context of cosmetic dentistry procedures you require. After a thorough examination, we will explain what situation you have and what corrective measures are possible.

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